# 求三个数的和
def sum_num(a,b,c):
    return a+b+c


# 求三个数的平均值
def average_num(a,b,c):
    return sum_num(a,b,c)/3  # 嵌套调用


print(sum_num(1,2,3))
print(average_num(1,2,3))
